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Artigos de revistas sobre o assunto "Light Olefines"
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Du, Lingyin, Yueyang Han e Youhao Xu. "Effect of Molecular Structure of C10 Hydrocarbons on Production of Light Olefins in Catalytic Cracking". Catalysts 13, n.º 6 (16 de junho de 2023): 1013. http://dx.doi.org/10.3390/catal13061013.
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The effect of the molecular structure of feedstock on the cracking reaction of C10 hydrocarbons to ethylene and propylene over H-ZSM-5 zeolite was investigated. To better compare the effect of decane on the production of light olefins, the thermal cracking and catalytic cracking performance of decane were first investigated. As a comparison, the thermal cracking and catalytic cracking of decane were studied by cracking over quartz sand and H-ZSM-5. Compared with the thermal cracking reaction over quartz sand, the catalytic cracking reaction of decane over H-ZSM-5 has a significantly higher conversion and light olefins selectivity, especially when the reaction temperature was lower than 600 °C. On this basis, the catalytic cracking reactions of decane and decene over H-ZSM-5 were further compared. It was found that decene with a double bond structure had high reactivity over H-ZSM-5 and was almost completely converted, and the product was mainly olefin. Compared with decane as feedstock, it has a lower methane yield and higher selectivity of light olefins. Therefore, decene was more suitable for the production of light olefins than decane. To this end, we designed a new light olefin production process. Through olefin cracking, the yield of light olefins in the product can be effectively improved, and the proportion of different light olefins such as ethylene, propylene and butene can be flexibly adjusted.
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Vosmerikov, Anton A., Ludmila N. Vosmerikova e Alexander V. Vosmerikov. "STUDYING THE INFLUENCE OF ALKALINE TREATMENT AND MODIFICATION OF ZEOLITE ON ITS PHYSICAL-CHEMICAL AND CATALYTIC PROPERTIES IN THE PROCESS OF PROPANE CONVERSION TO OLEFIN HYDROCARBONS". ChemChemTech 67, n.º 8 (23 de julho de 2024): 50–58. http://dx.doi.org/10.6060/ivkkt.20246708.11t.
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In this work, the effect of alkaline treatment of ZSM-5 zeolite with a modulus of 100 on its physicochemical properties and activity in the process of converting propane into olefin hydrocarbons was investigated. The growing demand for lower olefins is driving the search for new ways to improve existing technologies and develop new, more efficient catalysts. Catalytic dehydrogenation of light alkanes is an alternative to the petrochemical method for producing lower olefins from cheap and available gas and oil and gas feedstocks. At the same time, dehydrogenation reactions of light alkanes have a number of features and limitations that determine the range of possible catalysts. Zeolites are a class of supports that, due to their large surface area, nanometer-sized pores, and good thermal stability, can be used to prepare catalysts for the dehydrogenation of C2−C4 alkanes. An important feature of crystalline high-silica zeolites is the ability to change their acidic properties under the influence of various pre-treatments, which opens up great opportunities for their regulation and, accordingly, the selection of the most effective catalyst for a particular chemical process. It has been shown that alkaline treatment of zeolite leads to the formation of an additional amount of mesopores, which, in turn, affects its catalytic properties in the process of converting propane into olefinic hydrocarbons. The dependence of the activity and selectivity of the zeolite catalyst on the concentration of the alkali solution used for its treatment has been established. It was found that treatment of the zeolite catalyst with a 1.0 M NaOH solution leads to an increase in its selectivity with respect to the formation of C2–C4 olefins from propane, which at a process temperature of 650 °C reaches 32.0% with a propane conversion of 81%. It has been shown that additional promotion of desilicated zeolite with magnesium or manganese increases its activity with respect to the formation of olefinic hydrocarbons from propane. For citation: Vosmerikov A.A., Vosmerikova L.N., Vosmerikov A.V. Studying the influence of alkaline treatment and modification of zeolite on its physical-chemical and catalytic properties in the process of propane conversion to olefin hydrocarbons. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 50-58. DOI: 10.6060/ivkkt.20246708.11t.
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Pawelec, Barbara, Rut Guil-López, Noelia Mota, Jose Fierro e Rufino Navarro Yerga. "Catalysts for the Conversion of CO2 to Low Molecular Weight Olefins—A Review". Materials 14, n.º 22 (17 de novembro de 2021): 6952. http://dx.doi.org/10.3390/ma14226952.
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There is a large worldwide demand for light olefins (C2=–C4=), which are needed for the production of high value-added chemicals and plastics. Light olefins can be produced by petroleum processing, direct/indirect conversion of synthesis gas (CO + H2) and hydrogenation of CO2. Among these methods, catalytic hydrogenation of CO2 is the most recently studied because it could contribute to alleviating CO2 emissions into the atmosphere. However, due to thermodynamic reasons, the design of catalysts for the selective production of light olefins from CO2 presents different challenges. In this regard, the recent progress in the synthesis of nanomaterials with well-controlled morphologies and active phase dispersion has opened new perspectives for the production of light olefins. In this review, recent advances in catalyst design are presented, with emphasis on catalysts operating through the modified Fischer–Tropsch pathway. The advantages and disadvantages of olefin production from CO2 via CO or methanol-mediated reaction routes were analyzed, as well as the prospects for the design of a single catalyst for direct olefin production. Conclusions were drawn on the prospect of a new catalyst design for the production of light olefins from CO2.
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Natarajan, Palani, Deachen Chuskit e Priya. "Readily available alkylbenzenes as precursors for the one-pot preparation of buta-1,3-dienes under DDQ visible-light photocatalysis in benzotrifluoride". Organic Chemistry Frontiers 9, n.º 5 (2022): 1395–402. http://dx.doi.org/10.1039/d1qo01869h.
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By using DDQ visible-light photocatalysis, an olefin-free method for the production of buta-1,3-dienes is disclosed. DDQ* converts alkylbenzenes to olefins and then olefins to buta-1,3-dienes in a consecutive manner.
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Liu, Fei, Ting Li, Peng Long Ye, Xiao Dan Wang, Jian Xin Cao e Duan Hua Guo. "Effect of Fe Loading Content on Catalytic Performance of ZSM-5 for the IMTO Process". Advanced Materials Research 648 (janeiro de 2013): 135–38. http://dx.doi.org/10.4028/www.scientific.net/amr.648.135.
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Among the processes for production of olefins, methanol converted to light olefins with methyl iodide as intermediate is a potential and an alternative route, which can be realized under mild condition. ZSM-5 catalyst is considered to be an effective catalyst for methanol to light olefins, better performances for olefins can be obtained by modifying. In this paper, the methanol to olefin with iodide reaction (IMTO) has been studied in a small scale fixed bed reactor over Fe modified ZSM-5 catalyst. It is indicated that ZSM-5 zeolites were modified with Fe loadings successfully, as a result the pore sizes reduced availably comparing with ZSM-5, the conversion of methanol and selectivity of light olefins got 98.8% and 89.5% respectively when modified with 9% Fe loadings.
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Kang, Jong Hun. "Development of shape selectivity theory of methanol-to-olefins reaction over small-pore zeolite molecular sieves". Ceramist 25, n.º 2 (30 de junho de 2022): 145–58. http://dx.doi.org/10.31613/ceramist.2022.25.2.01.
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The methanol-to-olefins reaction is regarded as an important technology capable of meeting today’s rising demand for light olefins. The regioselective confinement effect of small-pore, cage-type zeolites on hydrocarbon pool intermediates results in strong shape selectivity determining the product olefin distribution. Despite decades of effort, a direct correlation between zeolite cage topologies and olefin selectivity distributions had remained elusive. The cage-defining ring theory is the first general catalytic shape selectivity theory that can predict the selectivity distribution of product light olefins from the given crystallographic information of the small pore zeolite catalysts. This article outlines the development procedure of the cagedefining ring theory. To aid readers’ comprehension, brief introductions to the structures and properties of zeolites and related molecular sieves, which are an important class of ceramic catalysts, are also provided.
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Yahyazadeh, Arash, Ajay K. Dalai, Wenping Ma e Lifeng Zhang. "Fischer–Tropsch Synthesis for Light Olefins from Syngas: A Review of Catalyst Development". Reactions 2, n.º 3 (21 de julho de 2021): 227–57. http://dx.doi.org/10.3390/reactions2030015.
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Light olefins as one the most important building blocks in chemical industry can be produced via Fischer–Tropsch synthesis (FTS) from syngas. FT synthesis conducted at high temperature would lead to light paraffins, carbon dioxide, methane, and C5+ longer chain hydrocarbons. The present work focuses on providing a critical review on the light olefin production using Fischer–Tropsch synthesis. The effects of metals, promoters and supports as the most influential parameters on the catalytic performance of catalysts are discussed meticulously. Fe and Co as the main active metals in FT catalysts are investigated in terms of pore size, crystal size, and crystal phase for obtaining desirable light olefin selectivity. Larger pore size of Fe-based catalysts is suggested to increase olefin selectivity via suppressing 1-olefin readsorption and secondary reactions. Iron carbide as the most probable phase of Fe-based catalysts is proposed for light olefin generation via FTS. Smaller crystal size of Co active metal leads to higher olefin selectivity. Hexagonal close-packed (HCP) structure of Co has higher FTS activity than face-centered cubic (FCC) structure. Transition from Co to Co3C is mainly proposed for formation of light olefins over Co-based catalysts. Moreover, various catalysts’ deactivation routes are reviewed. Additionally, techno-economic assessment of FTS plants in terms of different costs including capital expenditure and minimum fuel selling price are presented based on the most recent literature. Finally, the potential for global environmental impacts associated with FTS plants including atmospheric and toxicological impacts is considered via lifecycle assessment (LCA).
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Gholami, Zahra, Fatemeh Gholami, Zdeněk Tišler, Martin Tomas e Mohammadtaghi Vakili. "A Review on Production of Light Olefins via Fluid Catalytic Cracking". Energies 14, n.º 4 (19 de fevereiro de 2021): 1089. http://dx.doi.org/10.3390/en14041089.
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The fluid catalytic cracking (FCC) process is an alternative olefin production technology, with lower CO2 emission and higher energy-saving. This process is used for olefin production by almost 60% of the global feedstocks. Different parameters including the operating conditions, feedstock properties, and type of catalyst can strongly affect the catalytic activity and product distribution. FCC catalysts contain zeolite as an active component, and a matrix, a binder, and a filler to provide the physical strength of the catalyst. Along with the catalyst properties, the FCC unit’s performance also depends on the operating conditions, including the feed composition, hydrocarbon partial pressure, temperature, residence time, and the catalyst-to-oil ratio (CTO). This paper provides a summary of the light olefins production via the FCC process and reviews the influences of the catalyst composition and operating conditions on the yield of light olefins.
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Salah Aldeen, Omer Dhia Aldeen, Mustafa Z. Mahmoud, Hasan Sh Majdi, Dhameer A. Mutlak, Khusniddin Fakhriddinovich Uktamov e Ehsan kianfar. "Investigation of Effective Parameters Ce and Zr in the Synthesis of H-ZSM-5 and SAPO-34 on the Production of Light Olefins from Naphtha". Advances in Materials Science and Engineering 2022 (24 de fevereiro de 2022): 1–22. http://dx.doi.org/10.1155/2022/6165180.
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In this paper, Ce and Zr modified commercial SAPO-34 and H-ZSM-5 catalysts were synthesized via a wet impregnation method and used as catalysts for the production of light olefins from naphtha. The synthesized catalysts were characterized using SEM, TGA, XRD, BET, and NH3-TPD. Thermal catalytic cracking of parent catalysts (SAPO-34 and H-ZSM-5) and modified catalysts with Ce and Zr on the production of light olefins from naphtha has been studied. The effects of different loading of Ce (2–8 wt.%), Zr (2–5 wt.%), and different temperatures on the yield of ethylene and propylene were also investigated. The yield of ethylene and propylene improved by 21.78 wt% and 23.8 wt%, respectively, over 2% Ce and 2% Zr on SAPO-34 catalyst. This is due to the higher acid sites on the surface of modified catalysts. It was found that H-ZSM-5 with 2% Zr loading has the highest yield of light olefins (40.4%) at 650°C in comparison with unmodified parent catalysts, while Ce loading has less effect on the olefin yield compared to Zr loading. Finally, simultaneous loading of Ce and Zr showed no effect on the light olefin yield owing to the significant decline of acid sites.
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Gholami, Zahra, Fatemeh Gholami, Zdeněk Tišler, Jan Hubáček, Martin Tomas, Miroslav Bačiak e Mohammadtaghi Vakili. "Production of Light Olefins via Fischer-Tropsch Process Using Iron-Based Catalysts: A Review". Catalysts 12, n.º 2 (28 de janeiro de 2022): 174. http://dx.doi.org/10.3390/catal12020174.
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The production of light olefins, as the critical components in chemical industries, is possible via different technologies. The Fischer–Tropsch to olefin (FTO) process aims to convert syngas to light olefins with high selectivity over a proper catalyst, reduce methane formation, and avoid the production of excess CO2. This review describes the production of light olefins through the FTO process using both unsupported and supported iron-based catalysts. The catalytic properties and performances of both the promoted and bimetallic unsupported catalysts are reviewed. The effect of support and its physico-chemical properties on the catalyst activity are also described. The proper catalyst should have high stability to provide long-term performance without reducing the activity and selectivity towards the desired product. The good dispersion of active metals on the surface, proper porosity, optimized metal-support interaction, a high degree of reducibility, and providing a sufficient active phase for the reaction are important parameters affecting the reaction. The selection of the suitable catalyst with enhanced activity and the optimum process conditions can increase the possibility of the FTO reaction for light-olefins production. The production of light olefins via the FTO process over iron-based catalysts is a promising method, as iron is cheap, shows higher resistance to sulfur, and has a higher WGS activity which can be helpful for the feed gas with a low H2/CO ratio, and also has higher selectivity towards light olefins.
Teses / dissertações sobre o assunto "Light Olefines"
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Corda, Massimo. "Catalyst Design and Mechanistic Insights into COx Hydrogenation to Methanol and Light Olefins". Electronic Thesis or Diss., Université de Lille (2022-....), 2024. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2024/2024ULILR037.pdf.
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L'augmentation de la concentration de CO2 atmosphérique présente des défis environnementaux significatifs et souligne l'urgence de développer des procédés chimiques durables. Une approche prometteuse pour aborder ces problèmes est la conversion catalytique du CO2 en produits chimiques à valeur ajoutée, tels que le méthanol et les oléfines légères. Cette thèse se concentre sur le développement de catalyseurs pour la synthèse de méthanol et la synthèse d'oléfines légères à partir de CO2 par médiation de méthanol. De plus, l'hydrogénation du CO médiée par le méthanol en oléfines légères est également étudiée: le CO peut être considéré comme une alternative au CO2, car il peut être produit par la réaction du gaz à l'eau inverse. Les travaux rapportés dans cette thèse fournissent de nouvelles perspectives sur la conception de catalyseurs pour l'hydrogénation de COx en méthanol ou en oléfines légères, en suggérant de nouvelles stratégies pour améliorer la sélectivité des produits. De plus, la thèse fait progresser la compréhension des aspects mécanistiques de ces réactions. Pour l'hydrogénation du CO2 en méthanol, le catalyseur commercial CuO-ZnO-Al2O3 a été promu avec des halogènes (Br, Cl, I) pour améliorer la sélectivité au méthanol. Il a été observé que le Br permettait d'améliorer la sélectivité de 10 % par rapport au catalyseur initial. Une analyse cinétique a montré que le Br entraînait la suppression de la réaction de conversion inverse de l'eau en gaz et de la réaction de décomposition du méthanol, toutes deux responsables de la production parallèle de CO. Pour l'hydrogénation du CO2 en oléfines légères médiée par le méthanol, une série de catalyseurs bifonctionnels basés sur des oxydes de Zn, In, Mn, Cr ou Ga et différents zéolithes SAPO-34 a été étudiée. L'analyse des corrélations sélectivité-conversion a permis d'élucider les fonctions de chaque composant du catalyseur. Il a été découvert que la sélectivité aux oléfines légères au sein des fractions d'hydrocarbures dépendait finalement du composant zéolithique et diminuait en fonction du rendement en hydrocarbures. Le composant catalyseur à base d'oxyde métallique était responsable de la conversion du CO2, de la sélectivité globale aux hydrocarbures et au CO. La morphologie et l'acidité du SAPO-34 ont été identifiées comme des descripteurs majeurs de la sélectivité aux oléfines légères sans CO dans l'hydrogénation du CO2 sur des catalyseurs bifonctionnels. Enfin, pour la synthèse d'oléfines légères médiée par le méthanol à partir de gaz de synthèse, ce travail a étudié l'activité d'un catalyseur bifonctionnel composé de nanoparticules d'argent supportées mélangées à la zéolithe SAPO-34. Les catalyseurs résultants ont montré une sélectivité plus élevée aux oléfines légères par rapport à un catalyseur conventionnel oxyde-zéolithe. Il a été observé que la réaction est sensible à la structure, et la taille des particules d'argent influence la sélectivité aux oléfines légèresThe increasing concentration of atmospheric CO2 presents significant environmental challenges and emphasizes the urgency for sustainable chemical processes. One promising approach to address this issues is the catalytic conversion of CO2 into value-added chemicals, such as methanol and light olefins. This thesis focuses on the catalyst development for the methanol synthesis and the methanol-mediated light olefins synthesis from CO2. Moreover, the methanol-mediated CO hydrogenation to light olefins is also studied: CO can be considered as an alternative to CO2, as it can be produced by the Reverse Water Gas Shift reaction. The work reported in this thesis provides new insights into catalyst design for the COx hydrogenation to methanol or light olefins, suggesting new strategies to improve product selectivity. Additionally, the thesis advances the understanding of mechanistic aspects of these reactions. For the CO2 hydrogenation to methanol, the commercial CuO-ZnO-Al2O3 catalyst was promoted with halogens (Br, Cl, I), to improve selectivity to methanol. It was observed that Br allowed to improve the selectivity of 10 % compared to the pristine catalyst. A kinetic analysis showed that Br caused the suppression of the Reverse Water Gas Shift reaction and of the methanol decomposition reaction, both responsible of the parallel production of CO. For the methanol-mediated CO2 hydrogenation to light olefins, a series of bifunctional catalysts based on oxides of Zn, In, Mn, Cr, or Ga and different SAPO-34 zeolites were studied. The analysis of the selectivity-conversion correlations allowed to elucidate the functions of each catalyst component. It was uncovered that the selectivity to LO within hydrocarbon fractions depended ultimately on the zeolite component and decreased as a function of hydrocarbon yield. The metal-oxide catalyst component was responsible for the CO2 conversion, overall hydrocarbon and CO selectivity. The SAPO-34 morphology and acidity were identified as major descriptors of the CO-free LO selectivity in the CO2 hydrogenation over bifunctional catalysts. Finally, for the methanol-mediated synthesis of light olefins from syngas, this work studied the activity of a bifunctional catalyst composed by supported silver nanoparticles mixed with SAPO-34 zeolite. The resulting catalysts exhibited higher selectivity to light olefins compared to a conventional oxide-zeolite catalyst. It was observed that the reaction is structure-sensitive, and the silver particle size influences the selectivity to light olefins
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Aitani, Abdullah Mohamed. "Synthesis of light olefins from methanol". Thesis, City University London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357480.
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Vu, Xuan Hoan, Sura Nguyen, Thanh Tung Dang, Udo Armbruster e Andreas Martin. "Production of renewable biofuels and chemicals by processing bio-feedstock in conventional petroleum refineries". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-190806.
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The influence of catalyst characteristics, i.e., acidity and porosity on the product distribution in the cracking of triglyceride-rich biomass under fluid catalytic cracking (FCC) conditions is reported. It has found that the degradation degree of triglyceride molecules is strongly dependent on the catalysts’ acidity. The higher density of acid sites enhances the conversion of triglycerides to lighter products such as gaseous products and gasoline-range hydrocarbons. The formation of gasolinerange aromatics and light olefins (propene and ethene) is favored in the medium pore channel of H-ZSM-5. On the other hand, heavier olefins such as gasoline-range and C4 olefins are formed preferentially in the large pore structure of zeolite Y based FCC catalyst (Midas-BSR). With both catalysts, triglyceride molecules are mainly converted to a mixture of hydrocarbons, which can be used as liquid fuels and platform chemicals. Hence, the utilization of the existing FCC units in conventional petroleum refineries for processing of triglyceride based feedstock, in particular waste cooking oil may open the way for production of renewable liquid fuels and chemicals in the near futureBài báo trình bày kết quả nghiên cứu khả năng tích hợp sản xuất nhiên liệu sinh học và hóa phẩm từ nguồn nguyên liệu tái tạo sinh khối giầu triglyceride bằng công nghệ cracking xúc tác tấng sôi (FCC) trong nhà máy lọc dầu. Kết quả nghiên cứu cho thấy xúc tác có ảnh hưởng mạnh đến hiệu quả chuyển hóa triglyceride thành hydrocarbon. Tính acid của xúc tác càng mạnh thì độ chuyển hóa càng cao và thu được nhiều sản phẩm nhẹ hơn như xăng và các olefin nhẹ. Xúc tác vi mao quản trung bình như H-ZSM-5 có độ chọn lọc cao với hợp chất vòng thơm thuộc phân đoạn xăng và olefin nhẹ như propylen và ethylen. Với kích thước vi mao quản lớn, xúc tác công nghiệp FCC dựa trên zeolite Y ưu tiên hình thành C4 olefins và các olefin trong phân đoạn xăng. Ở điều kiện phản ứng của quá trình FCC, triglyceride chuyển hóa hiệu quả thành hydrocarbon mà có thể sử dụng làm xăng sinh học cho động cơ và olefin nhẹ làm nguyên liệu cho tổng hợp hóa dầu
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Silva, Júnior José Roberto da. "Craqueamento de hidrocarbonetos naftênicos sobre zeólitas HZSM-12 modificadas – rendimento e seletividade a olefinas leves". Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/8273.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
It was studied the catalytic performance of ZSM-12 zeolites modified by desilication in the cracking of naphthenic hydrocarbons. ZSM-12 zeolites with nominal a SiO2/Al2O3 ratio were synthesized during 96 or 144 h under hydrothermal conditions and the obtained zeolites were treated with NaOH solutions under different conditions. The samples were characterized by thermogravimetric analysis (TA), X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 physisorption, temperature programmed desorption of ammonia (NH3-TPD), 27Al MAS NMR spectroscopy, energy-dispersive X-ray spectroscopy (EDX) and infrared spectroscopy (Py-FTIR). The treatment with NaOH solutions under mild conditions was more effective for the ZSM-12 zeolite synthesized during 96 h. For the HZ12-96-0,2 sample, obtained by treatment at 35 °C with 0.2 mol.L-1 NaOH solution during 15 min, it was verified an increase in the external surface area and the formation of mesopores in the range of 2 to 14 nm. On that zeolite occurred a higher yields to light olefins during the cracking of cyclohexane at 400 °C and also in the cracking of methyl and ethylcyclohexane at 450 °C. This result was mainly related to the higher density of acid sites exhibited by the HZ12-96-0,2 zeolite compared with the parent ZSM-12 one, as consequence of the applied alkaline treatment. It was also verified that the ZSM-12 zeolites modified by more severe alkaline treatment (0.5 or 1.0 mol.L-1 NaOH solution at 80 °C for 30 min) presented significant increase of the external surface area and mesopores volume. The catalytic cracking of cyclohexane, methylcyclohexane and ethylcyclohexane at 500 °C, as well as the physicochemical characteristics of the MZ12-96-0,5 zeolite enhanced the formation of light olefins. The highest yield to light olefins was obtained on that zeolite during the cracking of ethylcyclohexane, which increased 9% when compared with the yield obtained on the not modified HZSM-12 zeolite. The selectivity to light olefins on the studied HZSM-12 zeolites was strongly influenced by presence of a side chain in the naphthenic ring (methyl or ethyl), as well as by the employed cracking operating conditions.
Estudou-se o desempenho de zeólitas ZSM-12 modificadas por dessilicalização no craqueamento de hidrocarbonetos naftênicos. Zeólitas ZSM-12 com razão SiO2/Al2O3 igual a 80 foram sintetizadas em 96 ou 144 h sob condições hidrotérmicas. As zeólitas ZSM-12 obtidas foram modificadas sob diferentes condições de tratamento alcalino com soluções de NaOH e posteriormente caracterizadas por termogravimetria, difratometria de raios X, microscopia eletrônica de varredura, fisissorção de nitrogênio, dessorção de amônia à temperatura programada, ressonância magnética nuclear do 27Al, espectroscopia de energia dispersiva de raios X e espectroscopia na região do infravermelho com adsorção de piridina. O tratamento alcalino, sob condições mais brandas, foi mais efetivo para a zeólita ZSM-12 sintetizada em menor tempo de cristalização (96 h). Para a zeólita HZ12-96-0,2, obtida por tratamento com solução de NaOH 0,2 mol.L-1 a 35 °C por 15 min, verificou-se um aumento na área superficial externa e distribuição de tamanho de mesoporos entre 2 e 14 nm. Nessa zeólita, ocorreu um maior rendimento a olefinas leves no craqueamento de cicloexano a 400 °C e, também, no craqueamento de metil- e etil-cicloexano realizado a 450 °C. Esse resultado foi relacionado, principalmente, com a maior concentração de sítios ácidos na zeólita HZ12- 96-0,2, em relação à zeólita HZSM-12 precursora, como consequência do tratamento alcalino. Verificou-se, também, que as zeólitas ZSM-12 modificadas por tratamento alcalino, sob condições mais severas (solução de NaOH 0,5 ou 1,0 mol.L-1 a 80 °C por 30 min), apresentaram aumento significativo de área superficial externa e volume de mesoporos. O craqueamento de cicloexano, metil- e etil-cicloexano realizado a 500 °C, assim como as características físicas e químicas da zeólita MZ12-96-0,5, favoreceram a formação de olefinas leves. O maior rendimento a olefinas leves ocorreu durante o craqueamento do etil-cicloexano sobre essa zeólita, com aumento desse rendimento em torno de 9% quando comparado ao rendimento obtido sobre a zeólita HZSM-12 não modificada. A seletividade a olefinas leves sobre as zeólitas HZSM-12 preparadas neste estudo sofreu forte influência da presença da cadeia lateral no anel naftênico (metil ou etil), assim como também das condições operacionais de craqueamento empregadas.
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Nqakala, Loyiso Clemence. "Hydrothermal synthesis of hierarchical ZSM-5 with different Si/Al ratio and their evaluation as catalysts in the catalytic cracking of hexane". University of Western Cape, 2021. http://hdl.handle.net/11394/8316.
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>Magister Scientiae - MScEthylene and propylene are greatly used for their importance as feedstocks for producing useful materials. Due to rise in prices and the demand of ethylene and propylene, the need to increase the selective production of these light olefins is necessary. To achieve this, zeolites, specifically ZSM-5 has been used to investigate catalytic cracking of several types of hydrocarbons for the production of these light olefins. This study focuses on developing hierarchical macro and/or mesoporous ZSM-5 zeolites with variable Si/Al ratios. The synthesized materials were then evaluated on their performance via catalytic cracking of hexane, dodecane and tyre derived oil [TDO] to produce light olefins, particularly ethylene and propylene.
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Albiero, Jalusa Konzen. "PRODUÇÃO DE OLEFINAS LEVES A PARTIR DE ETANOL EM ZSM-5 SINTETIZADA SEM DIRECIONADOR NITROGENADO". Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/7987.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe petrochemical industry is currently strongly based on the production of light olefins ethylene and propylene, which are mainly produced by hydrocarbons from oil. Due to the environmental appeal and unstable oil market scenario, alternative routes to the production of these olefins are being developed, meanly regarding the use of alcohol as raw material. In this context, ethanol is highlighted with Ethanol to Olefins Process (ETO), in which there is catalytic conversion via reactions of dehydration, oligomerization, cracking, isomerization, among others. This work aims to obtain ethylene and propylene from ethanol using ZSM-5 zeolite as catalyst in its acid form. The synthesis of this material was performed using non-conventional sources of silicon and aluminum, kaolin and silica extracted from rice husk ash, and in the absence of nitrogenous templates. The use of seeds was employed together with ethanol, which acts as cotemplate of the zeolitic structure, in different quantities, and in different silica/alumina ratios and crystallisation times. The influence of each of these variables was evaluated with the support of a full factorial experimental design on the final characteristics of the synthesized samples, such as relative crystallinity, chemical composition and textural properties. All samples presented the characteristic crystal structure of ZSM-5 as verified by both X-ray diffractograms and infrared spectra. However, samples with small amounts of seed and ethanol added to short periods of crystallization presented lower crystallinities and specific areas in comparison to other samples. On the other hand, the use of high quantities of seed can lead to the formation of quartz when the crystallization time is extended. With the catalytic tests of ethanol conversion into olefins it was possible to evaluate the influence of synthesis variables, the residence time and the concentration of ethanol in feed, proving the importance of all synthesis variables in the distribution of the reaction products The total conversion of ethanol was observed in all tests made, evidencing the high activity of hZSM-5 in the dehydration of ethanol to ethylene, being the propylene yield strongly influenced by the reaction temperature and characteristics of the catalitic material, with a maximum yield of 27% at 500 °C. The HZSM-5 presented high stability under reaction conditions while maintaining the production of ethylene for more than 40 hours of reaction, whereas the coke formation drastically reduces the production of propylene still in the early hours of reaction.
A indústria petroquímica atualmente está fortemente baseada na produção das olefinas leves eteno e propeno, que são principalmente produzidas através de hidrocarbonetos oriundos do petróleo. Em virtude do apelo ambiental e do instável cenário do mercado de petróleo, rotas alternativas para a produção destas olefinas estão sendo desenvolvidas, principalmente no que tange a utilização de álcoois como matéria-prima. Neste contexto, o etanol ganha destaque com o processo Ethanol to Olefins (ETO), no qual se tem conversão catalítica via reações de desidratação, oligomerização, craqueamento, isomerização, entre outras. O presente trabalho tem por objetivo a obtenção de eteno e propeno através de etanol empregando como catalisador a zeólita do tipo ZSM-5 na forma ácida. A síntese deste material foi realizada utilizando fontes não convencionais de silício e alumínio, o caulim e a sílica extraída da cinza da casca de arroz, e na ausência de direcionadores de estrutura nitrogenados. O emprego de sementes foi adotado juntamente com etanol, que atua como codirecionador da estrutura zeolítica, em diferentes quantidades, assim como em diferentes razões sílica/alumina e tempos de cristalização. A influência de cada uma destas variáveis foi avaliada com o auxílio do planejamento experimental fatorial completo nas características finais das amostras sintetizadas, como cristalinidade relativa, composição química e propriedades texturais. Todas as amostras obtidas apresentaram estrutura cristalina característica da ZSM-5, comprovada tanto nos difratogramas de Raios-X como nos espectros de absorção na região do Infravermelho. Entretanto, as amostras com pequenas quantidades de sementes e de etanol somadas a curtos períodos de cristalização apresentaram cristalinidades e áreas específicas reduzidas em relação às demais amostras. Em contrapartida, o emprego de elevadas quantidades de sementes pode levar a formação de quartzo quando o tempo de cristalização é prolongado. Com os testes catalíticos de conversão de etanol em olefinas foi possível avaliar a influência das variáveis de síntese, do tempo de residência e a concentração de etanol na alimentação, comprovando a importância de todas as variáveis de síntese na distribuição dos produtos da reação. A conversão total de etanol foi observada em todos os testes realizados, evidenciando a elevada atividade da HZSM-5 na desidratação de etanol a eteno, sendo o rendimento a propeno fortemente influenciado pela temperatura de reação e características do material catalítico, com máximo rendimento igual a 27% na temperatura de 500°C. A HZSM-5 apresentou elevada estabilidade nas condições de reação, mantendo a produção de eteno por mais de 40 horas de reação, enquanto que a formação de coque reduz drasticamente a produção de propeno ainda nas primeiras horas de reação.
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Vu, Xuan Hoan, Sura Nguyen, Thanh Tung Dang, Udo Armbruster e Andreas Martin. "Production of renewable biofuels and chemicals by processing bio-feedstock in conventional petroleum refineries". Technische Universität Dresden, 2014. https://tud.qucosa.de/id/qucosa%3A29110.
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The influence of catalyst characteristics, i.e., acidity and porosity on the product distribution in the cracking of triglyceride-rich biomass under fluid catalytic cracking (FCC) conditions is reported. It has found that the degradation degree of triglyceride molecules is strongly dependent on the catalysts’ acidity. The higher density of acid sites enhances the conversion of triglycerides to lighter products such as gaseous products and gasoline-range hydrocarbons. The formation of gasolinerange aromatics and light olefins (propene and ethene) is favored in the medium pore channel of H-ZSM-5. On the other hand, heavier olefins such as gasoline-range and C4 olefins are formed preferentially in the large pore structure of zeolite Y based FCC catalyst (Midas-BSR). With both catalysts, triglyceride molecules are mainly converted to a mixture of hydrocarbons, which can be used as liquid fuels and platform chemicals. Hence, the utilization of the existing FCC units in conventional petroleum refineries for processing of triglyceride based feedstock, in particular waste cooking oil may open the way for production of renewable liquid fuels and chemicals in the near future.Bài báo trình bày kết quả nghiên cứu khả năng tích hợp sản xuất nhiên liệu sinh học và hóa phẩm từ nguồn nguyên liệu tái tạo sinh khối giầu triglyceride bằng công nghệ cracking xúc tác tấng sôi (FCC) trong nhà máy lọc dầu. Kết quả nghiên cứu cho thấy xúc tác có ảnh hưởng mạnh đến hiệu quả chuyển hóa triglyceride thành hydrocarbon. Tính acid của xúc tác càng mạnh thì độ chuyển hóa càng cao và thu được nhiều sản phẩm nhẹ hơn như xăng và các olefin nhẹ. Xúc tác vi mao quản trung bình như H-ZSM-5 có độ chọn lọc cao với hợp chất vòng thơm thuộc phân đoạn xăng và olefin nhẹ như propylen và ethylen. Với kích thước vi mao quản lớn, xúc tác công nghiệp FCC dựa trên zeolite Y ưu tiên hình thành C4 olefins và các olefin trong phân đoạn xăng. Ở điều kiện phản ứng của quá trình FCC, triglyceride chuyển hóa hiệu quả thành hydrocarbon mà có thể sử dụng làm xăng sinh học cho động cơ và olefin nhẹ làm nguyên liệu cho tổng hợp hóa dầu.
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Ramos, Cristiano Pereira. "Catalytic essays and modeling of light olefin oligomerization". Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11474.
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Mestrado em Engenharia QuímicaNos últimos anos tem-se observado um aumento da procura de diesel, comparativamente com a gasolina. A produção de gasolina aumentou à custa do aparecimento das unidades de FCC. Deparando com este facto, a produção de diesel tem de acompanhar a sua crescente procura, e essa reposta encontra-se precisamente nestas unidades de FCC. Aquando a formação de gasolina nestas unidades, um dos subprodutos gerados em maior quantidade é a corrente de olefinas leves. As olefinas, na presença de um catalisador, e sujeitas a alta pressão e temperatura formam produtos de elevado valor comercial na gama do diesel. Nesta dissertação foi estudada, precisamente, a oligomerização de olefinas leves através de ensaios catalíticos. O processo consiste na combinação no mesmo reator, de um catalisador zeolítico a 200 com uma alimentação de buteno, acompanhado de um caudal de inerte para diluição do reagente. A oligomerização do 1-buteno permite obter produtos na gama diesel C10 a C20. A instalação experimental foi montada no início da dissertação. Antes da sua utilização, sucessivas correcções a nível de fugas, durante vários ciclos de aquecimento, tiveram de ser efectuadas de modo a deixá-la operacional. Foi utilizada para activação do catalisador, calibração do GC e para a realização da oligomerização de 1-buteno. Foi utilizado o catalisador zeolítico H-ZSM-5 comercial (Zeolyst CBV 3024E com uma razão Si/Al=15). Este catalisador devido à sua microporosidade e estrutura permite a ocorrência de selectividade de forma, que favorece a formação de produtos lineares. A instalação foi testada e foram efectuadas experiências a alta pressão (30 bar), tendo sido possível obter produtos na gama do diesel. Estes produtos foram identificados por cromatografia gasosa com um detector FID acoplado. Um modelo de equilíbrio e cinética foi estudado e programado de modo a prever o comportamento da reacção através da variação do tempo adimensional de reacção, pressão, temperatura e da alimentação.
In past years it has been observed an increase demand of diesel compared to gasoline. The production of gasoline has increased significantly after the installation of FCC units. During gasoline production, light olefins are obtained as side product. These light olefins, in the presence of a catalyst and submitted to high temperature and pressure, form high commercial products in diesel range. In this work, 1-butene oligomerization via zeolite catalysis was studied. The process can be conducted in a reactor with an acid catalyst at 200 with 1-butene diluted in nitrogen (feed) to form products in diesel range (C10-C20). The experimental set-up was assembled at the beginning of the thesis. Before use, successive leak tests, consisting of heating-cooling cycles, have been performed to leave the equipment operational. The installation is able to carry out the catalyst activation and 1-butene oligomerization. With respect to the catalyst, commercial H-ZSM-5 (Zeolyst CBV 3024E, Si/Al=15) has been used. This catalyst due its microporosity and its structure provides shape selectivity, which favours the formation of more linear products. The installation was tested and several runs were performed at high pressure (30 bar), which allowed to obtain diesel range products. Their identification was accomplished by gas chromatography with FID detector. The modeling of literature data was studied in order to predict the reaction behaviour for distinct sets of reaction time, pressure, temperature and feed concentration.
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Al, Wahabi Saeed M. H. "Conversion of methanol to light olefins on SAPO-34: kinetic modeling and reactor design". Texas A&M University, 2003. http://hdl.handle.net/1969.1/1579.
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In this work, the reaction scheme of the MTO process was written in terms of elementary steps and generated by means of a computer algorithm characterizing the various species by vectors and Boolean relation matrices. The number of rate parameters is very large. To reduce this number the rate parameters related to the steps on the acid sites of the catalyst were modeled in terms of transition state theory and statistical thermodynamics. Use was made of the single event concept to account for the effect of structure of reactant and activated complex on the frequency factor of the rate coefficient of an elementary step. The Evans-Polanyi relation was also utilized to account for the effect of the structure on the change in enthalpy. The structure was determined by means of quantum chemical software.
The number of rate parameters of the complete reaction scheme to be determined from experimental data is thus reduced from 726 to 30. Their values were obtained from the experimental data of Abraha by means of a genetic algorithm involving the Levenberg-Marquardt algorithm and combined with sequential quadratic programming.
The retained model yields an excellent fit of the experimental data. All the parameters satisfy the statistical tests as well as the rules of carbenium ion chemistry. The kinetic model also reproduces the experimental data of Marchi and Froment, also obtained on SAPO-34. Another set of their data was used to introduce the deactivation of the catalyst into the kinetic equations.
This detailed kinetic model was used to investigate the influence of the operating conditions on the product distribution in a multi-bed adiabatic reactor with plug flow. It was further inserted into riser and fluidized bed reactor models to study the conceptual design of an MTO reactor, accounting for the strong exothermicity of the process. Multi-bed adiabatic and fluidized bed technologies show good potential for the industrial process for the conversion of methanol into olefins.
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Darim, Hélio Rubens Abdo. "Propriedades ácidas e texturais de zeólitas ZSM-5 dessilicalizadas ou desaluminizadas – análise do rendimento e seletividade a olefinas leves durante a transformação de cicloexano e metilcicloexano". Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/8580.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Nowadays, the Brazilian petroleum is extracted from very deep fields and possesses a high naphthenic hydrocarbons composition, which imposes new challenges to refineries and specially to the catalytic cracking process. In that process, the catalyst must act maximizing the production of the highly demanded gasoline, diesel and light olefins from heavy fractions. Taking into consideration the above discussed context, this work aimed to evaluate the effect of basic or acid treatments applied on ZSM-5 zeolites (Si/Al=12 or 23) in the activity to cyclohexane or methylcyclohexane transformation. XRD and 27Al-NMR showed that the dealuminated zeolites presented an increase in their crystallinity due to the extra-framework aluminum lixiviation. On the other hand, in the desilicated zeolites occurred a decrease in their crystallinity as a consequence of the extra-framework aluminum generation. MEV images do not evidence any morphological change that could have been produced by the acid or basic treatments, however, the desilicated ZSM-5 zeolites treated under harder conditions presented significant textural modifications. As expected, the chemical ICP analyses showed a decrease in the Si/Al ratio in the desilicated zeolites and an increase of that ratio for those dealuminated ones, being the last variation more significative in the external surface of the zeolite crystals, as was evidenced by XPS analyses. Data from NH3-TPD showed that the acid treatment resulted in a higher ratio of strong acid sites, which suffered more deactivation during reaction. N2 fisisorption analyses of the ZSM-5 zeolites, showed that the desilication done at higher temperature was more efficient to mesopore generation. In the cyclohexane and methylcyclohexane transformation, the dealuminated zeolites were less active due to their lower aluminum content, nevertheless were more stable and presented a small increase to light olefins selectivity. The desilicated ZSM-5 zeolites presented higher activity and higher yield to light olefins that were supported by their lower Si/Al ratio and mainly by the presence of mesoporosity that enhanced the reagents and products internal diffusivity.
A produção nacional de petróleo, extraído de jazidas cada vez mais profundas, possui um elevado teor de hidrocarbonetos naftênicos, o que impõe novos desafios às refinarias brasileiras e, em particular, ao processo de craqueamento catalítico. Nesse processo, o catalisador deve maximizar a transformação das frações pesadas em produtos de alta demanda como gasolina, diesel e olefinas leves. Nesse contexto, esta dissertação objetivou avaliar o efeito de tratamentos de lixiviação ácida ou básica em zeólitas ZSM-5 (Si/Al=12 ou 23), na atividade para a transformação de cicloexano ou metilcicloexano. Dados de DRX e 27Al-RMN mostraram que as zeólitas desaluminizadas apresentaram um aumento da sua cristalinidade devido à remoção de átomos de alumínio extra-rede, por outro lado, nas zeólitas dessilicalizadas ocorreu uma redução da cristalinidade devido à geração de alumínio extra rede. As micrografias de MEV não evidenciaram modificação morfológica devido aos tratamentos, entretanto nas amostras dessilicalizadas sob condições mais severas, houve significativa mudança das propriedades texturais. Como esperado, as análises químicas por ICP mostraram uma redução na razão Si/Al para as amostras dessilicalizadas e um aumento dessa razão para as zeólitas desaluminizadas, sendo essa variação mais significativa na superfície externa dos cristais, como mostraram resultados de XPS. As análises de DTP-NH3 mostraram que o tratamento ácido resultou numa maior proporção de sítios ácidos fortes, os quais sofreram maior desativação durante a reação. Dados de fisissorção de N2 das zeólitas mostraram que a dessilicalização em temperatura mais elevada foi mais eficiente na geração de mesoporos. Na transformação do cicloexano e do metilcicloexano, as zeólitas desaluminizadas apresentaram menor conversão como resultado da diminuição do teor de alumínio, entretanto tiveram maior estabilidade e apresentaram um ligeiro aumento na seletividade a olefinas leves. As amostras dessilicalizadas apresentaram maiores conversões e rendimentos a olefinas leves, que se justificaram em função da diminuição da razão Si/Al, mas principalmente, como resultado da presença de mesoporosidade, que melhorou a difusão interna de reagentes e produtos.
Capítulos de livros sobre o assunto "Light Olefines"
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Chen, N. Y., William E. Garwood e Francis G. Dwyer. "Applications in Alternate Fuels and Light Olefins". In Shape Selective Catalysis in Industrial Applications, Second Edition,, 212–37. 2a ed. Boca Raton: CRC Press, 2023. http://dx.doi.org/10.1201/9781003418207-7.
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Li, Zaiting, Wenyuan Shi, Xieqing Wang e Fuking Jiang. "Deep Catalytic Cracking Process for Light-Olefins Production". In ACS Symposium Series, 33–42. Washington, DC: American Chemical Society, 1994. http://dx.doi.org/10.1021/bk-1994-0571.ch004.
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Zhu, Genquan, Chaogang Xie, Zaiting Li e Xieqing Wang. "Catalytic Processes for Light Olefin Production". In Springer Handbook of Petroleum Technology, 1063–79. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49347-3_36.
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Molinari, M., M. Brunelli e M. Lunelli. "Computer-Aided Thermodynamic Analysis of Light Olefin Conversion". In The European Oil and Gas Conference, 560. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-010-9844-1_82.
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Kissin, Yury V. "Main Kinetic Features of Ethylene Polymerization Reactions with Heterogeneous Ziegler-Natta Catalysts in the Light of Multi-Center Reaction Mechanism". In Organometallic Catalysts and Olefin Polymerization, 217–28. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59465-6_18.
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Pickard, Andy. "Chapter 14 | Gaseous Fuels, Liquefied Petroleum Gases, and Light Hydrocarbons: Methane through Butanes, Natural Gasoline, and Light Olefins". In Significance of Tests for Petroleum Products: 9th Edition, 225–34. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2018. http://dx.doi.org/10.1520/mnl120170021.
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Inui, Tomoyuki. "Highly Selective Synthesis of Light Olefins from Methanol Using Metal-Incorporated Silicoaluminophosphate Catalysts". In ACS Symposium Series, 115–27. Washington, DC: American Chemical Society, 1999. http://dx.doi.org/10.1021/bk-2000-0738.ch008.
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Boddula, Rajender, Ramyakrishna Pothu, Ramachandra Naik, Ahmed Bahgat Radwan e Noora Al-Qahtani. "Iron-Based Catalysts for Fischer–Tropsch Synthesis for Light Olefins Production from Syngas". In Multifunctional Inorganic Nanomaterials for Energy Applications, 268–82. Boca Raton: CRC Press, 2024. http://dx.doi.org/10.1201/9781003479239-18.
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Martínez, Agustín, Maria A. Arribas e Sara Moussa. "Chapter 10. Application of Zeolites in the Production of Light Olefins and BTX Petrochemical Intermediates". In Catalysis Series, 351–408. Cambridge: Royal Society of Chemistry, 2017. http://dx.doi.org/10.1039/9781788010610-00351.
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Khani, Leyla, Hamidreza Haddadi, Gülden Gökçen Akkurt e Mousa Mohammadpourfard. "Design and Thermodynamic Analysis of a Novel Power, Methanol, and Light Olefins Trigeneration System Fed with Shale Gas". In Springer Proceedings in Energy, 273–80. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-30171-1_30.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Light Olefines"
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Mi, Jie, Fenyun Yuan e Jianan Zhang. "Transition metals-Modified SAPO-34 for methanol conversion to light olefins". In 2013 International Conference on Materials for Renewable Energy and Environment (ICMREE). IEEE, 2013. http://dx.doi.org/10.1109/icmree.2013.6893778.
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Agbajei, T. A., Georgios N. Karanikolos e Maryam Khaleel. "Zeolitic Imidazole Frameworks for Super Selective Separation of Propylene from Propane". In SPE Nigeria Annual International Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/217228-ms.
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Abstract Olefin and paraffin gases are important products of the petrochemical refining industry wherein their effective separation could provide high economic gains and competitiveness in the emerging energy markets amidst state-of-the-art technology. Important chemicals such as polyethylene and polypropylene are derived from raw materials in the form of light olefins, including ethylene and propylene, processible via naphtha cracking. However, since this leads to its production among other valuable by-products separation/refinement is required and this is commonly achieved through technical and energy-intensive cryogenic distillation due to the similarity in thermophysical properties of the process effluents. Thus, cost-effective and energy-efficient processes are required among which membrane-based separation techniques stand out. In that line, zeolitic imidazolium frameworks (ZIFs) have shown a superior potential to provide high selectivity and high permeability to particular species in a mixture they are used to refine. This superior effectiveness is attributed to ZIF's uniform pore sizes that enable sharp molecular sieving, as well as its highly porous structure that enables fast species transport through it, with minimal mass transfer hindrance for the targeted/preferably selected specie. Among ZIFs, there exists one called ZIF-8 which is especially suited to propylene/propane separation and has been widely reported for its sharp molecular sieving performance for this mixture. ZIF-8 is also distinctly stable, and relatively easy to synthesize from cheap and readily available starting materials. Recent advances in the fabrication methods reported for ZIF-8 synthesis are presented in this work, along with a comparison of the separation performance for propylene and propane resulting from different types of ZIF-8 produced by these methods. The potential effect of utilizing this ZIF material in the refining units applied for olefin/paraffin separation is also critically evaluated towards its industrial utilization.
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Tang, RuiYuan, Yuanyu Tian e Yingyun Qiao. "Bifunctional catalyst cracking gasification of vacuum residue for coproduction of light olefins and H2-rich syngas". In 2017 5th International Conference on Machinery, Materials and Computing Technology (ICMMCT 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/icmmct-17.2017.37.
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Нурмахаматов, Герман Владимирович, e Владислав Сергеевич Хрипко. "IMPROVING THE ENERGY EFFICIENCY OF THE REFINING PROCESS BY THE EXAMPLE OF THE ISOMERIZATION PROCESS". In Наука, общество, производство и промышленность: актуальные проблемы и перспективы: сборник статей международной научной конференции (Омск, Апрель 2023). Crossref, 2023. http://dx.doi.org/10.37539/230407.2023.66.59.002.
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Повышение энергоэффективности процесса нефтепереработки является одним из важных процессов, используемых современными нефтеперерабатывающими заводами для катализа твердых кислот из-за ограниченного содержания бензола, ароматических соединений и олефинов в бензине. Целью данной статьи является изучение влияния различных катализаторов на изомеризацию светлых нефтепродуктов. Improving the energy efficiency of the refining process is one of the important processes used by modern refineries for the catalysis of solid acids due to the limited content of benzene, aromatic compounds and olefins in gasoline. The purpose of this article is to study the effect of various catalysts on the isomerization of light petroleum products.
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Yu, Yajie, Shaojun Xia e Ming Zhao. "Production of entropy minimization of CO2 hydrogenation to light olefins unit reactor with linear phenomenological heat transfer law". In International Conference on Mechanical Engineering, Measurement Control, and Instrumentation, editado por Guixiong Liu e Siting Chen. SPIE, 2021. http://dx.doi.org/10.1117/12.2611264.
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Yu, Yajie, Shaojun Xia e Ming Zhao. "Production of entropy minimization of CO2 hydrogenation to light olefins unit reactor with linear phenomenological heat transfer law". In International Conference on Mechanical Engineering, Measurement Control, and Instrumentation, editado por Guixiong Liu e Siting Chen. SPIE, 2021. http://dx.doi.org/10.1117/12.2611264.
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Zhang, Yuxiang, Ryan Buntain, Jacob Edwards, Boian Alexandrov e Jorge A. Penso. "Evaluation of Susceptibility to Thermal Fatigue Cracking in High Temperature Alloys for Refinery Olefin Applications". In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21741.
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Abstract High carbon, Cr – Ni alloys are used for tubing in refinery olefin furnaces. During furnace operation, such tubes might be exposed to thermal shock and fatigue loading, which may result in cracking and/or complete rupture. The objective of this study was to develop and validate a testing procedure for evaluation and ranking the susceptibility to thermal fatigue cracking in tubing of such Cr – Ni alloys. The proposed thermal fatigue testing procedure utilizes the Gleeble™ thermo-mechanical simulator and was developed to closely match extreme service conditions. Test samples with notched gauge section were subjected to repeating thermal cycles under fixed displacement to restrict the sample expansion and contraction, during heating and cooling, and simulate high level of structural restraint. The temperature range of thermal cycling was between 1110°F (600°C) and 2040°F (1115°C) with heating rate of 10,000°F/hr (1.54°C/s) and cooling rate of 83,462°F/hr (12.88°C/s). The following parameters were recorded and used for ranking the thermal fatigue cracking susceptibility: number of cycles to failure, stress vs. time integral, maximum experienced tensile and compressive stresses, and change in gauge section area. All failed test samples were subjected to fracture surface analysis using scanning electron microscopy. The non-failed samples were examined for notch cracks using binocular microscope at up to x100 magnification. The gauge section of all tested samples was characterized with light optical and scanning electron microscopy to correlate crack nucleation and propagation to susceptible microstructural constituents.
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Jou, Rong-Yuan. "Measurements for the Moisture Permeations and Thermal Resistances of Cyclo Olefin Copolymer Substrates Deposited a Silicon Dioxide Film". In ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52130.
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Plastic substrates for organic light-emitting devices (OLED) are extremely sensitive to moisture and oxygen. A new amorphous engineering thermoplastic, nominated cyclic olefin copolymer (COC) has been used for this application, because of higher transparence, lower birefringence, lower dispersion and lower water absorption. However, COC plastic substrates can’t sustain plasma-based processing temperatures at 350°C. In this study, experiments of the moisture permeation rate testing and the thermal resistance experiments are conducted to explore the moisture diffusion barrier and thermal barrier characteristics of COC substrate deposited a SiO2 thin film on it. Silicon dioxide layer of thickness, 0.25μm, 0.5μm, and 1 μm, respectively, are fabricated by PECVD. For the permeation rate measurement, the Ca-test method is adopted. For the thermal resistance measurements, two methods of the thermocouple in vacuum environment and the IR thermography are adopted and measured results are compared. Different surface temperatures, 323.15K, 373.15K, 408.15K, and 473.15K, respectively, are applied upon the silicon dioxide film and temperature differences for varied thickness of silicon dioxide film are measured. Experimental results are presented to investigate the behaviors of moisture diffusion barrier and thermal barrier characteristics of the COC/SiO2 structure.
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Souza, J. A., J. V. C. Vargas, O. F. von Meien e D. I. Vlassov. "A Simplified Numerical Model to Predict the Velocity Field in a Catalytic Cracking Unity in Oil Refineries". In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/htd-24301.
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Abstract This paper introduces a general computational model for determining the velocity field in either reacting or non-reacting duct flows. The model is then applied to a catalytic cracking unit (FCC) of an oil refinery, to determine the velocity field inside the riser, where reactions take place to convert heavy petroleum fractions in lighter products, like middle distillates and light olefins, with high rates of conversion and productivity. The correct approach to simulate this process is to avoid the plug flow assumption and to solve the full fluid flow problem, based on the mass and momentum conservation equations in a complete formulation, which are shown in the literature to be computationally very expensive and time consuming, mainly in a three-dimensional (3-D) simulation. Since, the main objective of the simulation is the accurate determination of the concentration of the noble products, a very accurate velocity field is not mandatory. Therefore, bidimensional flow is assumed, and a modified set of unsteady mass and momentum conservation equations is proposed and the resulting 2-D differential equations are discretized in space using an upwind cell centered finite differences method, and the equations integrated in time with an implicit backward Euler scheme. The coarsest possible mesh is determined such that the solution relative error is within 5 % when compared to a steady state accurate finite element solution, which was obtained with a 2-D isoparametric, four-noded, linear element that was implemented to solve the complete Navier-Stokes equations for the finite element analysis program, FEAP [1]. The objective of this work is to propose an alternative technique that gives a simplified treatment to the velocity field, to make possible the numerical calculation of the products concentrations in the riser and future application in optimization and real time control. Each cell, in this specific situation, can be understood as a perfect mixing reactor.
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Maceli, Nicola, e Gianfranco Maffulli. "An Industrial Methodology for Erosion Analysis of FCC Expander Blades". In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14891.
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Abstract Fluid Catalytic Cracking (FCC) is a process for the conversion of heavy stocks recovered from different refinery operations into high-octane gasoline, light fuel oils and olefin rich light gases. Zeolite particles are used as catalyst in the process to facilitate the cracking of long hydro-carbon molecules. Because of the contact between catalyst and feedstock, coke deposits on the catalyst active surface reducing its activity, air is used to remove it from the catalyst, in the regenerator. The coke burning produces a hot flow of flue gas with a valuable energy content (700°C – 3bar) that can be recovered using a Hot Gas Expander HGE before releasing the exhausts in the atmosphere. The flue gas is carrying a certain amount of catalyst so the expander hot parts (mainly blades but also the stator vanes) are constantly exposed to an abrasive medium that may compromise the reliability of the asset. Understanding how the solid particle erosion works is one of the challenges that HGEs designer shall deal with. To this purpose, a numerical approach was developed to account for some of the factors that are known to play a major role in erosion phenomena: particle velocity, angle of impact, composition and particle size, as well as the mechanical properties of the target surface at the operating temperature. The methodology was then applied to a cascade blade for which erosion data collected in a stationary erosion test rig are available. The comparison between numerical and experimental data showed a good agreement therefore providing confidence on the proposed methodology. Finally, the numerical procedure has been applied to a real case to show the effect of the different catalyst load on the life of the blades.
Relatórios de organizações sobre o assunto "Light Olefines"
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Farnand, B. A., R. K. Lennox e R. D. Tharby. Octane improvement by etherification of light distillate olefins. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1988. http://dx.doi.org/10.4095/304410.
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Stoimenov, Peter. Final report: Direct conversion of Light Hydrocarbons to Olefins. Office of Scientific and Technical Information (OSTI), maio de 2022. http://dx.doi.org/10.2172/1869574.
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Sanyal, Udishnu, Fan Lin e Peipei Wang. Conversion of Syngas and CO2 to Light Olefins using Multi-Functional Catalysts. Office of Scientific and Technical Information (OSTI), setembro de 2023. http://dx.doi.org/10.2172/2001273.
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Li, Meijia, e Udishnu Sanyal. Conversion of Syngas to Light Olefins and Oxygenates using Multi-Functional Catalysts. Office of Scientific and Technical Information (OSTI), setembro de 2024. http://dx.doi.org/10.2172/2476863.
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Dagle, Vanessa, e Robert Dagle. Conversion of syngas into light olefins in one step for process-intensified production of sustainable aviation fuels. Office of Scientific and Technical Information (OSTI), setembro de 2022. http://dx.doi.org/10.2172/1984521.
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